====== ATP-binding cassette transporter ======

The ATP-binding cassette [[transporter]]s are a transport system superfamily that is one of the largest and possibly one of the oldest [[gene]] families. It is represented in all extant phyla, from prokaryotes to humans. ABC transporters belong to translocases.
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The activity of these proteins, severely reduces the amount of therapeutics that penetrates the [[tumor cell]]s. Roy et al. hypothesized that ABC transporter expression could correlate with [[survival]] surrogates. They assessed the [[expression]] of four commonly expressed ABC transporters in [[GBM]] samples and investigated if [[mRNA]] levels could serve as a [[prognostic biomarker]].

Methods: Human specimens were analyzed by qPCR to assess [[ABCB1]], ABCC1/3 and [[ABCG2]] expression. Kaplan-Meier and multivariate analyses were then used to evaluate the correlation with [[overall survival]] (OS) and [[progression-free survival]] (PFS).

The cohort included 22 non-tumoral samples as well as 159 GBM tumor specimens. ABC transporters were significantly more expressed in GBM samples compared to non-tumoral tissue. Moreover, ABCC1 and 3 mRNA expression were significantly increased at recurrence. Statistical analyses revealed that increased expression of either ABCC1 or ABCC3 did not confer a poorer prognosis. However, increased ABCC1 mRNA levels did correlate with a significantly shorter PFS.

The expression of the four ABC transporters evaluated would not be suitable [[prognostic biomarker]]s. They believe that when estimating [[prognosis]], the plethora of mechanisms implicated in [[chemoresistance]] should be analyzed as a multi-facetted entity rather than isolated units
((Roy LO, Lemelin M, Blanchette M, Poirier MB, Aldakhil S, Fortin D. Expression of ABCB1, ABCC1 and 3 and ABCG2 in glioblastoma and their relevance in relation to clinical survival surrogates. J Neurooncol. 2022 Nov 7. doi: 10.1007/s11060-022-04179-1. Epub ahead of print. PMID: 36342588.)).